Various organic and inorganic compounds and materials have heretofore been used or proposed for use for reducing corrosive attack of metal surfaces of various water systems, such as recirculating cooling towers and the like. The aeration of the water in such recirculating water systems, containing high concentrations of dissolved oxygen, has been found particularly corrosive to ferrous and cupreous metal substrates. Of the various additive agents heretofore proposed, aqueous soluble chromate salts alone or in combination with other additive agents have been in widespread use in cooling water treatment systems. However, recent legislation, including the Federal Waters Protection Control Act, its amendments, and other related state and local statutes, have imposed restrictions on the use of toxic substances, including chromates, from being discharged into sewage systems due to the environmental hazards associated with aquatic life coming in contact therewith.
The process and composition of the present invention provides for an improved formulation suitable for use in various water systems comprising a carefully controlled combination of specific compounds in controlled effective concentrations, providing excellent corrosion inhibition of ferrous surfaces, as well as a suppression of scale formation and a corrosion inhibition of copper and copper-base alloys, which is effective in relatively small quantities, which is of economical use and which can, in many instances, be discharged to waste in compliance with environmental regulations without further treatment.